DCT has tendency to produce higher IOP results

July 12, 2011

Intraocular pressure (IOP) is higher when measured by dynamic contour tonometry (DCT) rather than Goldmann applanation tonometry (GAT).

Intraocular pressure (IOP) is higher when measured by dynamic contour tonometry (DCT) rather than Goldmann applanation tonometry (GAT), according to a study published in the Journal of Glaucoma.

An investigation led by Dr Guy Regev, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, USA, assessed the central corneal thickness (CCT) and GAT as well as DCT measurements in 116 open-angle glaucoma patients. GAT and DCT were evaluated in a randomized order, along with CCT in a single study visit. The agreement between GAT and DCT measurements were evaluated using Bland-Altman plots and the influence of CCT on IOP measurements was evaluated by multivariate regression analysis.

The findings revealed that using DCT to measure IOP was significantly higher than in GAT. There was a strong positive correlation between DCT and GAT IOP measurements in open-angle glaucoma patients. The Bland-Altman data demonstrated a variance on the amount of disagreement between the IOP measurement methods.

Both GAT and DCT measurements were not influenced by CCT. The results suggest there are alternative factors other than CCT as to why DCT produces significantly higher IOP results.